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Over the past month, I’ve been working on a new project. It’s called CherryBlossom, and it’s a way to write programs using haikus. Strictly speaking, CherryBlossom is a brainfuck analog. I actually spent more time writing the obligatory “Hello World” program in CherryBlossom than I did writing the interpreter for the language. The idea behind CherryBlossom is simple. Brainfuck instructions are mapped to words that convey the essence of the Brainfuck instruction. Of course, this is a little subjective and also a little abstract.

Ultimately, it serves as a way to make program code not just functional, but beautiful and artistic. Thus, we introduce a new criteria to programming. Your code must not only be elegant algorithmically, but must also be poetic and artistic (also, since program code consists of haikus, you need to represent your code in sets of 3 lines with the first and last lines having 5 syllables, and the second line 7. That is, conforming to haiku rules). CherryBlossom serves to blend the programmer and the poet into one entity (hopefully with amazing results).

Here is an example of “Hello World!” inCherryBlossom. I have opted to use a spruced up div tag instead of enclosing my beautiful poem in soulless sourcecode tags.Read the rest of this entry »

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A few days before I left India, I started writing a brainfuck interpreter in bAdkOde. I finished implemented all the instructions, excepting for looping. I actually finished the code (and fixed all bugs) while I was in the air, flying from Dubai to Los Angeles. Emirates Airlines has power-plugs for your laptop on the seat. It’s pretty sweet!

An interesting thing I noticed was that I couldn’t perfectly emulate the input instruction. I’m feeding the brainfuck code to the interpreter from STDIN and so that might be the problem. I’ve noticed that brainfuck interpreters written in brainfuck have the same problem. You have to specify program input before hand. This is what I’ve decided to do. You write brainfuck code, and then mark the end of program code by an exclamation mark. After the exclamation mark, you provide any input, and then mark the end of input by another exclamation mark. Programs that do not have any input end with two exclamation marks. After I finished writing the interpreter, I commented it. While I was doing this, I noticed a lack of labels in bAdkOde. So, I decided to update the interpreter to include them. Speaking of which, I really ought to rewrite the interpreter sometime…

Anyway, here is the code to the interpreter. I’m providing a link to it, because the commented version is rather large. But here’s the expanded (without labels or macros), unformatted version:

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In my previous post, I suggested that bAdkOde might be Turing Complete by writing a quine. One of the ways to actually prove Turing Completeness is to try and write an interpreter for another Turing-Complete language in bAdkOde. Another approach involves providing a direct translation from another Turing-Complete language into bAdkOde. Here, I prove the Turing Completeness of bAdkOde by providing a direct translation from Brainfuck into bAdkOde.Read the rest of this entry »

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I was talking to my CSE 200 (my first CS class at ASU) professor Richard Whitehouse about bAdkOde and he (rightly) pointed out that it didn’t have an explicit selection statement. He also said that unless I wanted it to be really ugly I’d need to have a selection statement. However, since I was going for ugly I figured that I’d just emulate the operation of an if and an if-else with the existing while statement.

If you know assembly, then you know that a while is simply a set of statements wrapped with a conditional branch at the top and a backwards branch at the bottom (or in other words, an if with a goto at the end. A do-while is simply a set of statements with a conditional branch (at the bottom) that branches to the top of the loop. In fact, in assembly programming there really aren’t any for loops or while loops. These keywords are simply abstractions and syntactic sugar. In bAdkOde, you can implement an if with the existing while statement if you explicitly make it break out of the loop. For example, let’s say that we want to check whether the user entered the character “0”:

?a
-48a
# print a line break
"10
# if a is zero
{=a
# print the string "zero"
"122"101"114"111"10
# set the a register to a non-zero value so that we can break out of the loop
>1a
}

I knew there was a way to implement an if-else with just while statements but I didn’t remember exactly how. Then my friend and co-worker Juan reminded me that I needed two variables. In our case, we need to use two registers:

?a
-48a
# copy the value of a into b
>ab
"10
# if a is zero
{=a
# print the string "zero"
"122"101"114"111"10
# set the a register to a non-zero value so that we can break out of the loop
>1a
}
# if the top loop failed, it means that b (which holds the same value as a) is
# non-zero and so we can enter this block.
# if the top loop was successful, it means that b (which holds the same value
# as a) is zero and so we won't enter this block. Hence, the second block acts
# as an 'else'
{!b
# print the string "non-zero"
"110"111"110"45"122"101"114"111"10
# zero out the b register
>0b
}

Yes, quite ugly. But that’s what I’m going for! 🙂

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I’ve added another project to the projects page. It’s called bAdkOde, an interpreter for an esoteric language that I designed. The very first incarnation of bAdkOde was written in Java and I actually posted it (or made a blog entry about it) over 8 years ago. For some reason I took it down. Probably because I stopped working on it. Anyway, I redesigned the language and wrote an interpreter for it in Perl about 4 or 5 years ago. I finally got around to posting it. Check out the project page for more details. Let me know what you think.

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I’ve finished work on the projects page. Sometimes I’ll have a passing interest in something that leads me to write some code for fun. Yes, you read right. I like to code… for fun. Anyway, this is something I’ve done ever since I started programming way back in 1991. I’ve written a bunch of cool little programs over the years. Most of these have been throwaway scripts that I wrote just to “see what would happen”. A few of these, however, have had some serious effort put into them. I’ve decided to showcase these on my site. Hopefully people will find them interesting :).

The project I’ve just uploaded is called Sulekha, and is a text-based Markov-chain generator. You can check it out here. The comments for this journal entry are mirrored on the Sulekha project page, so anything you post here will be visible there (and vice versa). Let me know what you think. Oh, and it’s interactive so you can generate your own text-based Markov-chains too!

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I am a pack rat. I keep anything and everything in the vague hope that I might need it someday. It doesn’t help when something like that does happen, and I DO need something. Then I feel vindicated and it only serves to re-enforce the behaviour. But anyway, I have these computer disks that are more than 11 years old. They are from 1994. They contain a bunch of GW-BASIC programs that I wrote. The disks are pretty damn old, and almost falling to pieces. I last used one (the one with all my code) about two years ago and did a directory listing. The only thing that did was screw it up even more. It’s now impossible to access the disk. But anyway, that’s on stupid Windows systems. I knew that I could still access data if I really wanted to – raw data. I put the disk into my FreeBSD machine and ran a dd command, while ignoring errors. It took a long time, but finally it dumped all my data out to a file. I then ran a strings command on it to get text. It was like a time-capsule. I saw all this code that I had writted more than a decade ago. I had been programming for at least two or three years then, but 1994 was when I wrote the most code, I think. I went out of my way to make the output messages from my program sound professional. But well, actually it all sounded kinda funny. However, if I hadn’t done any of that, I wouldn’t be where I am right now and I wouldn’t be doing what I do now. This was where it all started… where I became a programmer. Anyway, here are some snippets, along with my comments:Read the rest of this entry »

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I fnished my artificial life simulator over the weekend, and I have been running simulations on it. There were a few bugs initially that I quickly fixed. My initial simulations gave me some inexplicable “population explosion”. For example, in one cycle I would have 31 creatures and in the next cycle I would suddenly have around 9,000. It didn’t make very much sense until I analyzed the log files.

If any of you remember, I mentioned earlier that my “creatures” are nothing more than assembly programs. Each of these instructions (and parameters) translate into a bit pattern. Changes in the bit patterns lead to changes in the behaviour of the creature.

One of the instructions is a “reproduce instruction”. This prompts the creature to create a copy of itself, with possible mutations. The instruction has a parameter that tells the creature how many copies to create. During the course of the simulation, certain creatures evolved with the reproduce instruction as their first instruction.

My supervisor program (God program) runs one instruction of every creature during one cycle (sort of like an pre-emptive multitasking operating system). If a creature happens to reproduce during the current cycle, then the supervisor program will execute the child’s instructions as well in that current cycle. This led to an interesting situation. When the mutant that had the reproduce instruction as the first instruction reproduced, its child (if it didn’t have a mutation that changed the instruction) also had the reproduce instruction as the first instruction. So the supervisor program would run the child, and the child would reproduce with a similar offspring. This went on until a mutant that did not have a “reproduce instruction” as the first instruction, evolved. As you can see, this is what led to the population explosion. I corrected this problem by adding “sexual maturity” and “reproductive energy threshold” parameters to the creatures. Basically, a creature can reproduce only if it has been in existence for a certain number of cycles, and if its current energy is above its reproductive energy threshold. This got rid of the population explosion problem.

My simulations gave me some other interesting results. One of the instructions that I have is a MOV instruction. This instruction moves a creature from one cell in the two-dimensional array to another cell. There is a variant of this instruction, known as the MOVA instruction. In the MOV instruction, if the creature tries to move to an occupied cell, it will retreat to its original position. However, in the MOVA instruction the creature will try to kill (and subsequently eat) the occupant if the destination cell is occupied. I had created a creature that simply ate, reproduced, and moved to different cells. I noted that after many generations, this creature had evolved into an aggressive one, that would eat, reproduce, and move aggressively (MOVA) into other cells. That was rather interesting!

I also saw natural selection at work. When I corrected my population explosion problem, I made it so that the reproductive threshold of a creature was higher than its initial (starting) energy. Over the course of many cycles, I saw that the creatures evolved such that the initial energy would be very high, and that their reproductive threshold would be very low. In additon, their reproductive age was lowered. I thought that my creatures were having it too easy, so I modified my code to make reproduction a costly instruction. After running my simulation, I noticed the opposite! Now the creatures evolved such that the reproductive energy threshold would be much higher than their initial energy. It would seem that the creatures wanted to build up enough energy to where they would be able to reproduce successfuly.

There is also one very interesting behaviour that I noticed. I provide branch instructions in my instruction set. A creature can branch to any part of its code. In addition, I also have a Decrement and Branch instruction that is useful for iterative loops. One of my creatures evolved a clever strategy. It would decrement and branch into the middle of the branch instruction. When I analyzed the code, I noticed in doing so, the creature was performing a MOVA instruction in fewer bytes than writing an explicit MOVA instruction. It also had the added benefit of performing the MOVA instruction in an iterative fashion so that it could travel around the two-dimensional array. There was a reason for this kind of behaviour though. A creature consumes energy when it performs an instruction, and the energy consumption is proportional to its code size, so it is amazing, but not surprising that such behaviour could arise.

There is still more work that I need to do. I am thinking of giving my creatures some “memory” in the form of stack and RAM. They will have some Store, Load, Push and Pop instructions whereby they can write to and read from memory. Also, I am thinking of adding some more “registers”. Right now, the creatures have two count registers for performing iterative loops. My reason for adding more is this – I want the creatures to be able to act on the data in memory. For example, I can provide instructions that allow the creature to check the status of a particular cell, like if it is occupied, how much food it has, and so on. The creature can load data into the registers, and then use these registers as arguments for the cell checking instructions. This way I am hoping that my creatures will be able to evolve some rudimentary form of “intelligence”, or “intelligent” behavior. This will also increase my instruction set. Right now, if a mutation results in an invalid instruction, the creature dies when it tries to execute it. Actually, that reminds me – I had creatures that evolved with invalid instructions, but they had also evolved branch instructions that would jump over the invalid section of code!

Most of these complex behaviours aren’t that surprising when you consider natural selection… it is only err… natural that such behaviour should arise!

Well I guess that’s all I have for now. I might make a separate page for this project where I can describe this project in more detail. I’ll post more updates here after I run more simulations.